How do you know if you are on the compression stroke or exhaust stroke when you do the top end? I took apart the head and cylinder to replace the intake valves and change rings. I did the scotchbrite thing to clean the cylinder and used the service manual to reassemble, step by step. I have completely reassembled and only need to add radiator fluid to start up. I lined up all the timing marks per manual and tightened the cam sprocket with threadlocker. My guess is if it fires up, all is gravy, but if it doesn't, I reassembled it on the exhaust stroke and the spark plug will fire at the wrong stroke? Is there anyway to know??